Tracker Calibration - Line of Sight Method
Developers: Daniel J. Sandin, Dave Adamczyk, Greg Dawe, Marek Czernuszenko, Morteza Ghazisaedy, Robert V. Kenyon, Thomas A. DeFanti
Widely used in VR electro-magnetic trackers are sensitive to electrically or magneticly conductive objects in the environment. Static errors as high as 40% (4 feet) have been observed near the maximum range of the tracker. To correct for these errors usually a calibration lookup table is implemented. Data reported by the tracker hardware is corrected according to the table. There are different approaches to creating the lookup table. Two approaches of correcting these static errors are described by Bryson  and Ghazisaedy . Both of these methods require precision placement of the receiving sensor in a large number of positions. Because this process involves so many and precise measurements of 3D location, the process of gathering data is time consuming. A much faster method of creating the calibration table is “The Line of Sight Method”.
Date: March 1, 1995 - February 1, 1998